Hello everybody, I hope I'm in the right place here, for my question, if not please ignore or maybe point me to a better place. For start, I'm quit new to the whole GSM stack and still in the process of understanding it, so please if you have the feeling I maybe misunderstood something horrible, I probably have! Feel free to point that out :D. I working together with other peoble on a project witch aims to connect refugee camps in the middle east, to enable easy, safer and non profit communication between them, this is often a big need for example to find relatives, but also to communicate with in the camps because sometimes they are huge etc.. One part (an at the moment my part) of this is to build up independent GSM Networks per camp witch are interconnected with the other camps. The idea is to build GSM networks with in the camp witch are autonomous. If there is power they run, if there is internet peoble can call the other camps (if they have internet). Every thing need's to be done without any central entity (like an HLR for all camps, run on a Server in Frankfurt) so that when, let say government xy decides to only allow nation wide networking an cut's the internet (happened since I'm here 2 times, it's annoying as f**k), the camp's within the country and in the camp it self can still communicate. The question is how to do this interconnection? As fare as I understand in classical GSM infrastructure, this is done by SS7, but since we are not interested (at least by know) to interconnect with "big" providers, and also I did not found an open source implementation (but maybe I missed it) this seems not an option, so the plan now is to do this over VPN's and SIP/VOIP Server (probably asterisk). We like to be able to scale the camps number, and to be relative easy to maintain so we can enable people to run this them self (after we learned to run this our self of course ;)). And these protocols are fare better documented then SS7 so also much more esay to learn and to debug. We are still testing and researching and so I thought it is maybe a good time to ask her if this is a valid way or I missing something, or maybe you can point me towards some documentations where people did some similar things. We are all not professionals and do this more or less with learning by doing, but we don't need to do all the mistakes other did before us :D (maybe some but not all) thx in advance and for this great project witch enabled us to do stuff like this naif